Li3/8Sr7/16−xAxZr1/4Nb3/4O3 (A = Ca, Ba) ceramics were prepared by the conventional solid-state reaction method. The structures of prepared ceramic materials changed from cubic perovskite to tetragonal tungsten bronze with increasing barium (Ba) content as indicated by the x-ray diffraction (XRD) patterns. Li3/8Sr7/16−xBaxZr1/4Nb3/4O3 (x = 0.05, 0.10) samples are mixtures of perovskite and tetragonal tungsten bronze phases. Calcium ions (Ca2+) can partially occupy the Sr sites, and thus the cubic perovskite structure remains intact. However, an unknown phase could form because of a complete substitution of Ca for Sr; the ionic conductivity measured by the alternating-current impedance spectra of samples decreases with increasing Ba and Ca content. Parent Li3/8Sr7/16Zr1/4Nb3/4O3 exhibits the highest ionic conductivity of 1.23 × 10−5 S cm−1 at 25°C. Additionally, a half cell of LiFePO4/Li performed well in charge–discharge experiments, retaining a discharge capacity of 87.9 mAhg−1 after 300 cycles when Li3/8Sr7/16Zr1/4Nb3/4O3 was selected as the solid electrolyte separator.

中文翻译：

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Li3/8Sr7/16−xAxZr1/4Nb3/4O3 (A = Ca, Ba) 锂离子固体电解质的结构和电导率

Li3/8Sr7/16-xAxZr1/4Nb3/4O3 (A = Ca, Ba) 陶瓷是通过常规固相反应方法制备的。如X射线衍射（XRD）图所示，随着钡（Ba）含量的增加，制备的陶瓷材料的结构从立方钙钛矿转变为四方钨青铜。Li3/8Sr7/16−xBaxZr1/4Nb3/4O3 (x = 0.05, 0.10) 样品是钙钛矿和四方钨青铜相的混合物。钙离子 (Ca2+) 可以部分占据 Sr 位点，因此立方钙钛矿结构保持完整。然而，由于 Ca 完全取代 Sr，可能形成未知相。通过样品的交流阻抗谱测量的离子电导率随着 Ba 和 Ca 含量的增加而降低。母体 Li3/8Sr7/16Zr1/4Nb3/4O3 在 25°C 下表现出最高的离子电导率，为 1.23 × 10−5 S cm−1。